Prices of U.S. single-family homes in January plunged a record 19.0 percent from a year earlier, indicative of a U.S. housing market that is still in the throes of a deep recession, according to a Standard & Poor's/Case-Shiller report on Tuesday.

The composite index of 20 metropolitan areas fell 2.8 percent in January from December, S&P said of the index that dates back to 2000.

The U.S. housing market is in the worst downturn since the Great Depression as a huge supply of unsold homes, tighter lending standards and record foreclosures push down home prices.

The drops on a month-over-month as well as year-over-year basis were bigger than expectations based on a Reuters survey of economists.

Out of the 20 metro areas, 13 areas showed record rates of annual decline in January, and 14 areas reported declines in excess of 10 percent versus January 2008.

S&P said its composite index of 10 metropolitan areas declined 2.5 percent in January from December for a 19.4 percent year-over-year drop, also a record. The 10-city index dates back to 1988.

As of January 2009, average home prices across the United States are at similar levels to what they were in late 2003. From the peak in the second quarter of 2006, the 10-City Composite is down 30.2 percent and the 20-City Composite is down 29.1 percent.

Home prices, which peaked in mid-2006, continued their decline in 2009, David M. Blitzer, Chairman of the Index Committee at Standard & Poor's, said in a statement.

There are very few bright spots that one can see in the data, he said.

Most parts of the country appear to remain on a downward path, with all of the 20 metro areas reporting annual declines, and nine of the them falling more than 20 percent in the last year, Blitzer said.

The rate of decline in the two composites are very close to that rate and these have been reporting consecutive annual record declines since October 2007, he said.

The monthly data follows a similar trend, with the 10-City and 20-City Composite showing thirty consecutive months of negative returns, he said.

The battered U.S. housing market is critical to the U.S. economy, with a wide-ranging impact from the construction industry to the sale of appliances and furniture. After hurting growth for multiple quarters, a continued deterioration could prolong a turnaround for the world's largest economy, which has been in a recession since late 2007.

(Editing by Chizu Nomiyama)